Replaceable probe head

ABSTRACT

A probe head is disclosed that is detachable from a probe body containing electronics. The probe head including a housing enclosing a sensor and at least part of an electrical connector electrically coupled to the sensor. The housing has a coupling member positioned to detachably connect the housing to the probe body, and when the probe head and probe body are coupled, the electrical connector electrically couples the sensor to the electronics in the probe body.

TECHNICAL FIELD

The present application relates to a replaceable probe head, and moreparticularly to a replaceable probe head having a sensor, such as anelectrode, and having a connector for sealably connecting the probe headto a probe body.

BACKGROUND

Probes having sensors are known, but in the past once the sensor dies,in particular when a fluid reservoir of an electrode type sensor isspent, the entire probe was discarded. That may not have been tooexpensive prior to “smart probes,” but now that probes, like thosedisclosed herein, carry an on-board circuit board with memory andnumerous other functionalities, it is expensive to just throw away theentire probe.

To solve this problem and address this long-felt need, Applicants havedeveloped a replaceable probe head that allows the body of the probehousing the circuit board to be reused. In the embodiment disclosedherein, only the probe head is discarded.

SUMMARY

One aspect of the invention is a replaceable and/or disposable probehead for use with a probe body containing electronics. The probe headincludes a housing that encloses a sensor and at least part of anelectrical connector electrically coupled to the sensor. When the probehead is detachably connected to the probe body, the electrical connectorwill electrically couple the sensor to the electronics in the probebody. To form the detachable connection, the housing includes a couplingmember positioned to detachably connect the housing to the probe body.The coupling member may be a flexible open ring having a snap-fitfeature, for example, an annular ridge protruding from the exteriorsurface of the open ring for coupling the probe head to the probe body.The open ring is compressible toward a closed ring position to couplethe probe head to the probe body, expands to interconnect the two, andis compressible again to uncouple the probe head.

Another aspect of the invention is a probe for monitoring at least oneparameter of an environment that includes the replaceable probe head.The probe includes a probe body enclosing electronics that include afirst electrical connector electrically coupled thereto and at leastpartially enclosed by the probe body, and a probe head enclosing asensor and at least part of a second electrical connector electricallycoupled to the sensor. Either of the probe head or the probe bodyincludes a coupling member positioned to detachably connect the probehead and the probe body to one another. The coupling member detachablyconnects the probe head and the probe body with the first electricalconnector connected to the second electrical connector to electricallycouple the sensor of the probe head to the electronics of the probebody.

In one embodiment, the probe body also has a third electrical connectorelectrically coupled to the electronics in the probe body. The thirdelectrical connector is connectable to a monitoring device, for example,a sonde, that can operate and/or communicate with the probe, inparticular, with the electronics of the probe body and, hence, thesensor in the probe head. The third electrical connector may be awet-mateable connector.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of one embodiment of a probe having a replaceableprobe head.

FIG. 2 is an exploded assembly view of the probe of FIG. 1.

FIG. 3 is a side view of the replaceable probe head without theretaining clip.

FIG. 4 is a cross-sectional view of the replaceable probe head of FIG. 3taken along line 4-4.

FIGS. 5-6 are connector end views of alternate embodiments of thereplaceable probe head.

FIG. 7 is a top view of the retaining clip of the replaceable probehead.

FIG. 8 is a front view of the retaining clip of FIG. 7.

FIG. 9 is a cross-sectional view of the probe body.

FIG. 10 is a cross-sectional view of the probe of FIG. 1.

FIGS. 11-12 are distal end views of alternate embodiments of the probebody.

FIG. 13 is a front view of another embodiment of the replaceable probehead.

FIG. 14 is a top perspective view of a sonde that includes the probe ofFIG. 1.

FIG. 15 is an exploded assembly view of one embodiment of a probe.

DETAILED DESCRIPTION

The following detailed description will illustrate the generalprinciples of the invention, examples of which are additionallyillustrated in the accompanying drawings. In the drawings, likereference numbers indicate identical or functionally similar elements.

Referring to FIG. 1, a probe, generally designated 100, is shown thathas a distal end 130 and a proximal end 131 and may include a removableprobe head 102 removeably coupled to a probe body 104 by a couplingmember 110, a connector 106, a connecting collar 108, and a guard 112having one or more windows 113. The probe 100 can monitor parameters ofan environment using a sensor 114 housed within the probe head 102,typically an environment surrounding the distal end 130 of the probe,i.e., the probe head, when connected to another device by connector 106and, optionally, by the connecting collar 108. The connecting collar 108may be threaded for connecting the probe to a port in the device. Theconnector 106 may include a stop ring 228 to retain the collar 108,i.e., to keep the collar from sliding off.

Referring to FIG. 14, in one embodiment, the probe 100 may be connectedto a sonde 500, like the sonde described in U.S. Pat. No. 6,779,383,modified to include the probe disclosed herein. The sonde 500 includes aplurality of probes having various sensing capabilities. For example,the sonde 500 may include a turbidity sensor 510, a dissolved oxygensensor 512, the probe 100 having the replaceable probe head that in oneembodiment includes a pH electrode and/or an ORP electrode, atemperature-conductivity sensor 516 and a sensor 518, which can be achlorophyll or rhodamine sensor. The sonde 500 may also include a wiperelement 520 about which a wiper media such as a foamed rubber wiper padis wrapped and extending therefrom beyond the diameter of the sensor itis mounted on, the turbidity sensor 510 in FIG. 14 is a brush 524 forcleaning the surface of the sensors. In another embodiment, the probe100 may be connected to a sensor adaptor, a datalogger, a computer, ahandheld monitoring unit, or any other mobile or fixed data collectionplatform capable of connecting to the probe and communicating with thesensor therein to monitor the environment surrounding the sensor.

The probe 100 includes a sensor 114 housed within the housing 118 thatdefines at least part of the replaceable probe head 102. The sensor 114has access to the environment surrounding the distal end 130 of theprobe 100. In one embodiment, like that in FIG. 1, the sensor 114 mayprotrude from housing 118 and be surrounded by the guard 112. Thereplaceable probe head 102 may include a housing 118, which may be ahollow, generally cylindrical tube, with a sleeve 117 fixedly attachedto one end thereof. The replaceable probe head 102 may also include acoupling member 110 positioned on the sleeve opposite the distal end130. The coupling member removeably couples the replaceable probe head102 to the probe body 104, in particular to second housing 119.

The replaceable probe head 102, in particular its housing 118, sleeve117, and guard 112 may be a plastic material such as a suitableengineering thermoplastic material with good material strength thatlends itself to having the windows 113, the tabs 129, 129′, slots 182,182′ and/or annular grooves 116, 120, 122, described below, formedtherein. The thermoplastic may be water, corrosion, and/or chemicallyresistant, and electrically insulating. The plastic material should alsobe suitable for forming a watertight housing, in particular, havingwatertight bands between adjoining pieces. The watertight bond isimportant since the replaceable probe head 102 is often used under waterat significant depths and experiences increased pressure as it descends.If a gap occurs, water may be able to enter the replaceable probe head102 and damage its components.

The thermoplastic material may be an acetal, acrylic,acrylonitrile-butadiene-styrene terpolymer, a polyamide, apolycarbonate, a polyetherimide, a polyphenylene ether, a polyphenylenesulfide, a polysulfone, polyvinyl alcohol, or a thermoplastic polyester.In one embodiment, the thermoplastic material is an imide; preferably anon-filled imide, such as a polyetherimide. Polyetherimides arecommercially available under the brand name Ultem® available from SABICInnovative Plastics.

As shown in the assembly view of FIG. 2, the replaceable probe head 102may be inserted into the probe body 104, preferably using linear force,to couple the replaceable probe head 102 to the probe body 104 with awatertight seal. The replaceable probe head 102 may need to be partiallyinserted into the probe body 104 and rotated to align means to key thereplaceable probe head 102 to the probe body 104 for a proper connectionbefore applying further force to push the replaceable probe head 102into the probe body 104. The replaceable probe head 102 is removeablycoupled to the probe body 104 by the coupling member 110 and may beremoved by activating (e.g., compressing) the coupling member 110 andpulling with a linear force opposite of the force used to insert thereplaceable probe head 102.

Now referring to FIGS. 1-4, the replaceable probe head 102 has a firstend 184 and a second end 186, a housing 118 that houses a sensor 114 andat least part of an electrical connector 171 electrically coupled to thesensor 114, a coupling member 110 positioned to detachably connect thehousing 118 to the probe body 104, and a guard 112 to protect the firstend 184 where a portion of the sensor 114 may be positioned. In oneembodiment, the housing 118 may be a monolithic body having the couplingmember 110 integrally formed therewith or as a separate component. Inanother embodiment, the housing 118 may include a sleeve 117, which mayhave the coupling member, again, integrally formed therewith or as aseparate component.

The housing 118, best seen in FIGS. 3-4, has a first end 150 and asecond end 158 and may be a generally cylindrical, hollow housing. Thefirst end 150 defines a first opening 152 that may include one or moreports 199 (FIG. 10) and includes a first connecting means 156 on itsexterior surface proximate to the first opening. The first connectingmeans 156 may be continuous or discontinuous protuberances such asclips, snap-fit feature(s), threading, or other connecting features thatcan fixedly attach the guard 112 to the housing 118. The first end 150may have a smaller outer diameter than the central section 153 of thehousing, which facilitates the guard 112 fitting over the first end 150.In an alternate embodiment, the protuberances may be on the interior ofthe guard 112 and the first end 150 will, instead, have appropriatelypositioned and shaped recesses proximate to the first opening 152. Thefirst end 150 may also have a smaller inner diameter than the centralsection of the housing 118 such that an annular shoulder 154 is formedwhere the first end 150 transitions to the central section of thehousing. The annular shoulder 154 may be used to mount one or moresensors 114 within the first end 150 of the housing. In anotherembodiment, the guard 112 could fit inside the first end 150 rather thanover it, and both components would be shaped and configured accordingly.

The guard 112, as described above, is fixedly attachable to the firstend 150 of the housing 118 of the replaceable probe head. The guardincludes one or more windows 113 in the distal end of the guard 112. Theguard 112 may be a generally cylindrical, hollow sleeve that fits atleast partially over the first end 150 of the housing 118 to positionthe one or more windows 113 where the environment surrounding the guard112 has access to the sensor 114 or electrode 114′ of the replaceableprobe head 102.

The second end 158 of the first housing 118 defines an opening 159 inthe second end and includes a second connecting means 160 on itsexterior surface proximate to the opening 159. The second connectingmeans 160 may be any of the same connecting means discussed above forthe first connecting means 156 and may be the same or different as thefirst connecting means 156 on the housing 118. The second end 158 mayhave a smaller outer diameter than the central section of the housing118, which facilitates the second end 158 receiving the sleeve 117. Theouter diameter of the second end 158 may be the same as the outerdiameter of the first end 150 of the housing, but is not limitedthereto. In another embodiment, the sleeve 117 could fit inside thesecond end 158, and both components would be shaped and configuredaccordingly.

The sleeve 117 has a distal end 162 and a proximal end 164. The distalend 162 defines a first opening 166 that has a larger inner diameterthan the central section 176 of the sleeve 117. A first annular step 178is formed in the interior of the sleeve 117 where the distal end 162transitions to the central section 176. The first annular step 178 actsas a stop or seat for the second end 158 of the housing 118 when it isinserted into the open first end 166 of the sleeve 117. The distal end162 may include an annular groove or appropriately shaped and positionrecesses just interior to the first end 166 indented into the wallthereof. The groove or recesses are to receive the connecting means 160of the second end 158 of the first housing 118 for a watertightconnection. The sleeve 117 and housing 118 are preferably fixedlyattached together. In an alternate embodiment, the sleeve 117 may beintegral with the housing 118. If so, the second connecting means 160would be absent.

The exterior of sleeve 117 may include one or more annular groves 116,120, 122 indented therein. A first annular groove 116 may be positionedmost proximate to the housing 118 and may be wide enough to receive thecoupling member 110. The sleeve 117 may include a second annular groove120 between the first annular groove 116 and the proximal end 164 of thesleeve. The second annular groove 120 may be shaped to receive a firstsealing member 124, for example, an O-ring or the like. In anotherembodiment, there may be a third annular groove 122 between the secondannular groove 120 and the proximal end 164 of the sleeve 117 that isshaped to receive a second sealing member 126. While the embodimentsherein have three annular grooves with two of the grooves for receivingsealing members, one of skill in the art will appreciate that any numberof grooves and sealing members may be used. The sealing members 124, 126(FIG. 2) provide a watertight seal between the replaceable probe head102 and the probe body 104.

The proximal end 164 of the sleeve 117 defines a second opening 168 thathas a smaller inner diameter than the central section 176 of the sleeve117. As such, a second annular step 179 is formed in the interior of thesleeve 117 at the transition of the central section 176 to the secondopening 168. The second annular step 179 has seated thereon a circuitboard 170, such as a printed circuit board, that has a electricalconnector 171 extending from the circuit board 170 into or through thesecond opening 168. The electrical connector 171 may be a header witheither pins or sockets extending from the second opening 168, a cardedge connector, a printed circuit board connector, a USB connector, orany other known or later-developed connector that can connect the sensor114 or electrode 114′ to the circuit or circuit board 170 housed withinthe probe body 104. In the embodiment in FIGS. 3-6, the electricalconnector 171 is a male header with at least one active pin. One ofskill in the art will appreciate that not all the pins on a header needbe connected to the circuit board 170 on the opposite side of theheader. While the header shown has six pins, the electrical connector isnot limited thereto.

The circuit board 170 may be adhered to the sleeve 117 to hold it inplace and to form a watertight seal. Filler 180 may be present betweenthe electrical connector 171 and the second opening 168. Suitable filler180 seals the second opening 168 of the sleeve 117 so that water cannotenter and damage the components of the connector 171, the circuit board170, or the sensor 114. The filler 180 may be an adhesive, polymer, orother resin that provides a watertight protective seal of the opensecond end 168. For example, filler 180 may be an epoxy resin, siliconeRTV, potting compound, or any other suitable filler for forming awatertight seal. Connected to the circuit board 170 opposite theelectrical connector 171 is at least one lead 174 that extends throughthe sleeve 117 into housing 118 and connects the sensor 114 and/or itscomponents to the electrical connector 171.

The proximal end 164 of the sleeve 117 may also include a means to keythe replaceable probe head 102 to the probe body 104. In the embodimentof FIGS. 3-5, the means to key the replaceable probe head 102 is one ormore tabs 129, 129′ extending longitudinally from the proximal end 164of the sleeve 117. The first tab 129 and the second tab 129′ may havedifferent shapes as shown in FIG. 5, such that there is only oneorientation for insertion of the replaceable probe head 102 into theprobe body 104 to correctly connect the electrical connector 171 to thecircuit board 170 in the probe body 104. Accordingly, as seen in FIG.11, the first opening 136 of the probe body 104 receiving the electricalconnector 171 has a first slot 214 configured to receive the first tab129 and a second slot 215 configured to receive the second tab 129′. Inthe embodiment of FIG. 6, the means to key the replaceable probe head102 may be one or more slots 182, 182′ cut into the proximal end 164′ ofthe sleeve 117, with the slots preferably having different shapes.Accordingly, as seen in FIG. 12, the first opening 136 of the probe body104 receiving the electrical connector 171 has a first tab 216 and asecond tab 217 configured to be received in the slots 182, 182′,respectively, of the replaceable probe head 102. Many other means to keytwo parts together are known and are equally applicable here. Forexample, the proximal end 164 of the sleeve 117 may have a protrusion onthe outer surface thereof that fits into a slot indented and runninglongitudinally down the interior wall of the end of the probe body 104receiving the sleeve 117.

The sensor 114 housed within the replaceable probe head 102 may includea plurality of components, including an electrode 114′ (FIG. 10),window, membrane, or other surface positioned in or extending from thefirst end 150 of the housing 118, preferably in or extending from a port199 in the first end 150. The electrode 114′ may be an ion-selectiveelectrode. Any suitable ion-selective electrode or a combination of suchelectrodes may be housed by the probe head 102. For example, a pHelectrode, oxidation-reduction potential electrode, a dissolved oxygenelectrode, an electrode selective toward nitrite ions, nitrate ions,ammonia, fluoride ions, sodium ions, chloride ions, potassium ions,calcium ions, bromide ions, or manganese(II) ions. In one embodiment,the probe head 102 houses a pH electrode. In another embodiment, theprobe head 102 houses an oxidation reduction potential electrode. In yetanother embodiment, the probe head 102 houses both a pH electrode and anoxidation-reduction potential electrode.

An embodiment of a probe 100 having two sensors, in particular twoelectrodes 114′ extending from the first end 150 of housing 118, isrepresented in FIG. 10. The electrodes 114′ have their sensor components198 housed within housing 118 and connected to electrical leads 174 by asensor connector 200, for example, or electrical lead. The sensorcomponents 198 are those typically needed for the particular sensor orelectrode chosen for the parameter to be monitored. For a pH electrode,the sensor components 198 may include a sensor reservoir containing areagent that is consumed in making measurements with the sensor, forexample, an electrolyte filling solution such as KCl, a pH glasselectrode in fluid communication with the reservoir, a wire such as apure silver wire dipped in silver chloride to pass the signal from thesolution to the sensor connector 200, and a reference electrode, eitherseparate or built into the pH electrode itself. For anoxidation-reduction potential electrode, the sensor components 198 mayinclude similar components to the pH electrode such as the pure silverwire dipped in silver chloride surrounded by a reservoir containing anelectrolyte filling solution such as KCl, except that a nobel metal suchas platinum, gold, or silver is used as the measuring element ratherthan pH glass. The sensor components 198 for other types of electrodesor sensors are known and may be housed within housing 118.

The coupling member 110 may be any connecting feature that allows themating of the probe head 102 and the probe body 104 and the mating oftheir respective electrical connectors 171, 212 with a detachable,watertight connection.

Now referring to FIGS. 7-8, the coupling member 110 is a flexible openring 110 having a slot 111. In one embodiment, the open ring 110 isgenerally C-shaped. The flexibility of the ring 110 and slot 111 renderthe open ring 110 compressible or pinchable at least to the extent thatthe slot 111 may be closed when pressure is applied to the ring 110 onboth sides of the slot 111 and will return to its original position whenthe pressure is removed. Accordingly, the open ring 110 is compressibleor pinchable toward a closed ring position as shown by arrows A in FIG.7. The open ring 110 may also be expandable such that it may be expandedto widen slot 111, in particular, so that the open ring 110 may be slidover the sleeve 117 and into the first annular groove 116.

The exterior of the coupling member 110, best seen in FIG. 8, includesan upper portion 192 defining an open distal end 190 and a lower portion193 defining an open proximal end 191. The upper portion 192 overall hasa larger outer diameter compared to the lower portion 193. An annularstop 196 is defined where the upper portion 192 transitions to the lowerportion 193. The lower portion 193 includes a snap fit feature 128. Thesnap fit feature 128 is generally an annular snap fit feature, as itextends around the outer circumference of the open ring 110. The leadingedge 194 of the snap fit feature 128 may be beveled at an angle lessthan 90° to aide in pushing the snap fit feature 128 into the probe body104. The snap fit feature 128 is preferably an annular protuberance asshown in FIG. 8, but is not limited thereto. Inside and outside snap fitfeatures and/or other cantilevered snap fit features are all well knownand may be applicable here.

An advantage to the open ring 110 is that the replaceable probe head 102can be removed and replaced easily by anyone. Such components are oftenreferred to as “field replaceable,” which eliminates sending the probeto the manufacturer for replacement of the probe head.

The flexible open ring 110 detachably locks the probe head 102 and theprobe body 104 together upon insertion. The open ring 110 is compressedduring insertion into the probe body 104 and, due to its flexibility,expands outward into engagement with the probe body 104 once inserted.In the embodiment of FIG. 10, the snap-fit feature 128 of the open ring110 expands into engagement with, for example, an annular groove in theprobe body 104. The user may make insertion of the probe head 102 easierby pinching the open ring 110 toward a closed ring position A whileinserting or beginning to insert the probe head 102 into the probe body104.

When the probe head 102 is ready to be replaced (i.e., when an on-boardreservoir is used up, the probe head no longer works, etc.), theflexible open ring 110 is pinched toward a closed ring position A by theuser to disengage the open ring 110 from the probe body 104. The usermay pinch the open ring 110 between the thumb and at least one finger ofthe same hand. While pinching the open ring 110, the user pulls theprobe head 102 and the probe body 104 apart thereby disengaging theirrespective electrical connectors 171, 212. Now the spent probe head 102may be discarded and replaced with a new probe head.

An alternate embodiment for the coupling member 110 is shown on thereplaceable probe head 302 in FIG. 13. The replaceable probe head 302has an integral housing 318 that has a distal end 384 defining a firstopening 352 and a proximal end 386 defining a second opening 368. Here,the annular snap fit feature 328 is integrally formed on a couplingmember 319 of the housing 318. The coupling member 319, overall, has asmaller outer diameter than the rest of housing 318, such that anannular step 378 is defined at the transition from the coupling portion319 to the main body of housing 318. The exterior of coupling member 319may also include one or more annular groves indented therein. A firstannular groove 320 may be between the snap fit feature 328 and theproximal end 386. The first annular groove 320 may be shaped to receivea sealing member, for example, an O-ring or the like. The couplingmember 319 may also include a second annular groove 322 between thefirst annular groove 320 and the proximal end 386 that is also shaped toreceive a sealing member. While FIG. 13 illustrates two annular groovesin the coupling portion 319, the embodiment is not limited thereto. Thisembodiment has an effective coupling mechanism, but the probe head 302may need to be replaced by the manufacturer or a trained technician.

In another embodiment, the coupling member 110 may be a clip, a pushbutton-receiving aperture connection, threading, or other connectingfeatures that facilitate a detachable connection between the probe head102 and the probe body 104. These alternate coupling members may be usedalone or in combination with the open ring 110 discussed above or withone another. Any of these embodiments may include an O-ring or othersealing member to provide a watertight seal between the probe head 102and the probe body 104.

Now referring to FIG. 9, the probe body 104 has a second housing 119that is preferably a hollow, generally cylindrical tube having a distalend 132 and a proximal end 134. The distal end 132 defines a firstopening 136 and the proximal end 134 defines a second opening 137. Thehousing 119 has a substantially uniform outer diameter, but has threeinternal segments with different inner diameters. The interior of thehousing 119 has a cavity 138 at the distal end 132, an enlarged opening146 at the proximal end 134, and a chamber 144 therebetween.

The cavity 138 has a smaller inner diameter than the chamber 144 suchthat an annular shoulder 142 is defined at the transition between thecavity 138 and the chamber 144. The cavity 138 is generally sized toreceive the second end 186 of the replaceable probe head 102 includingthe snap fit feature 128 of the coupling member 110. Just interior tothe first opening 136 is an annular groove 140 indented into the wall ofthe cavity and extending around its periphery. The annular groove 140 isshaped and positioned so as to receive the snap fit feature 128protruding from the coupling member 110 when the replaceable probe head102 is connected to the probe body 104. It is appreciated that, while anannular groove is preferable, other indentation means are also possible.For example, the other indentation means may include a plurality ofrecesses formed in the cavity's wall arranged to coincide in alignmentwith a plurality of protuberances on the second end 186 of thereplaceable probe head 102.

The enlarged opening 146 at the proximal end 134 of the second housing119 extends generally uniformly into the interior of the housing 119 andis contiguous with the second opening 137 defined by the proximal end134. The enlarged opening 146 has a larger inner diameter compared tothe chamber 144 and may even have a larger inner diameter compared tothe cavity 138. The benefits of the enlarged opening 146, in particular,in relation to assembling and welding the assembly, are explained inApplicants' U.S. patent application Ser. No. 12/773,995 PROBE ANDPROCESS OF ASSEMBLING SAID PROBE (the “Assembly Process application”),filed the same day as this application, and incorporated herein byreference in its entirety.

The second housing 119 may be a metal and/or an anti-biofoulingmaterial. The metal may be water resistant and corrosive resistant. Forexample, the second housing 119 may be titanium, stainless steel,nickel, copper, and alloys thereof. In one embodiment, the secondhousing 119 is titanium. In another embodiment, the second housing 119is an antifouling copper-nickle alloy with a high copper content. Forexample, the antifouling copper-nickle alloy may be a 90-10 CuNi alloyor a 70-30 CuNi alloy. In another embodiment, the housing may be anantifouling plastic, for example, a polyethylene, polypropylene, ornylon that may include an anti-fouling compound such as capsaicin,capsicum, furan compounds, copper compounds, lactones, alkyl-phenols,organotin compounds, antibiotics, or mixtures thereof.

Now referring to FIG. 10, which is a cross-section of the embodiment inFIG. 1, the probe 100 includes the features of the replaceable probehead 102 discussed above including the open ring as the coupling member110 and a probe body 104 with housing 119 housing a circuit board 220,such as a printed circuit board. The circuit board 220 is mainly housedin chamber 144 and is connected to a platform 210 having a secondelectrical connector 212 extending therethrough. The platform 210 isseated on the annular shoulder 142, preferably the platform 210 isadhered thereto with a watertight seal, for example with an epoxyadhesive. The platform 210 and the second connector 212 are also shownin the end views of FIGS. 11-12 looking down into cavity 138 of thesecond housing 119 from the first opening 136.

The second electrical connector 212 may be the same as the firstelectrical connector 171 described above, but of a configuration thatwill mate with the first electrical connector 171. As shown in FIG. 10,the first connector 171 is a male header with six pins and the secondelectrical connector 212 is a female header with six receptaclesreceiving the pins.

Connector 106 is connected to the circuit board 220 at the end oppositeof the platform 210 by leads 222. The connector 106 includes at leastone male pin 224 and at least one female receptacle 225. Preferably, themale pin 224 and female receptacle 225 are wet mateable connectors.Connector 106 may also include a casing 226 surrounding at least partthereof, preferably, surrounding the part adjacent to the proximal end134 of second housing 119 to provide a surface for affixing theconnector 106 to the proximal end 134 with a watertight seal. The casing226 may be a metal and/or an anti-biofouling material such as thosediscussed above for the second housing 119. In one embodiment, thesecond housing 119 and the casing 226 are composed of the same materialand may be fixedly attached to one another, for example by laser weldingas disclosed in the Weld Method application. To enhance the attachmentbetween the second housing 119 and the casing 226, a reducing ring 148may be inserted into the enlarged opening 146 of the second housing 119to provide increased surface area for the weld.

Connector 106 may include a collar 108 on the casing 226 that isretained on the casing 226 by a stop ring 228 that fits within anannular groove indented into the end of the casing 226 opposite thesecond housing 119.

Referring now to FIG. 15, in another embodiment, a probe, generallydesignated 400, has a probe body 404 including an insertable male end408 having a first electrical connector therein and a coupling member410 positioned to detachably couple the probe body 404 to a probe head402. The first electronic connector may be similar to those describedabove for FIGS. 3-6. The insertable male end 408 may be part of theprobe body second housing 419′, and, in one embodiment, is integral withthe second housing 419. In another embodiment, the insertable male end408 is a separate component attached to housing 419. The insertable maleend 408 may also include one or more sealing members, such as O-rings424 and an alignment tab 429. The coupling member 410, as shown, is anopen flexible ring having a slot 411 and a snap-fit feature 428. Theopen flexible ring 410 may also have any of the features describedabove. The probe 400 may also include a connector 106 and threadedcollar 108, similar to those described above. The probe body 404 alsoincludes electronics, for example, a circuit board, housed within thesecond housing 419 to communicate with the sensor in the probe head 402.

The probe head 402 has a first housing 418 that houses a sensor and asecond electrical connector. The first housing 418 includes a female end459 for receiving the male end 408 of the probe body 404. The secondelectrical connector is preferably positioned in the female end 459 sothat the sensor in the probe head 402 can be electrically coupled to theelectronics in the probe body 404. The female end 459 and the secondelectrical connector may be similar to those described above for theprobe body of FIGS. 10-12.

When comparing the embodiments of FIGS. 2 and 15, the embodiment of FIG.2 may be preferable because it may be easier to replace the probe headhaving the coupling member and O-rings rather than replacing the O-ringson the probe body. The O-rings may wear or break after a plurality ofuses. Wear on the O-rings may prevent the O-rings from providing awatertight seal. Accordingly, the O-rings may need to be changed eachtime the probe head is replaced in the embodiment of FIG. 15.

In another embodiment, the probe may be mounted within a multi-probeassembly or sonde as illustrated in U.S. Pat. No. 6,779,383 and wipedwith a wiper element that cleans not only the disclosed probe 100, butother sensors in other probes.

It will be appreciated that while the invention has been described indetail and with reference to specific embodiments, numerousmodifications and variations are possible without departing from thespirit and scope of the invention as defined by the following claims.

What is claimed is:
 1. A probe head that is detachable from a probe bodythat contains electronics, the probe head comprising: a housingenclosing a sensor and at least part of an electrical connectorelectrically coupled to the sensor, the housing comprising a couplingmember positioned to detachably connect the housing to the probe body;wherein the electrical connector is electrically connectable to theelectronics in the probe body to electrically couple the sensor to theelectronics of the probe body; and wherein the coupling member includesa flexible, generally C-shaped open ring.
 2. The probe head of claim 1wherein the probe head is disposable.
 3. The probe head of claim 1wherein the flexible, generally C-shaped open ring includes a snap-fitfeature.
 4. The probe head of claim 3 wherein the snap-fit featureincludes an annular ridge protruding from the exterior surface of theopen ring.
 5. The probe head of claim 1 wherein the flexible, generallyC-shaped open ring is compressible to disengage the coupling member fromthe probe body such that the probe head is detachable from the probebody.
 6. The probe head of claim 5 wherein compressing the flexible,.generally C-shaped open ring reduces the ring's diameter.
 7. The probehead of claim 1 wherein the housing further comprises a first seat withthe flexible, generally C-shaped open ring seated thereon.
 8. The probehead of claim 7 wherein the housing includes a second seat having asealing ring seated thereon.
 9. The probe head of claim 1 wherein thecoupling member is integral with the housing.